


Defense

by Werepirechick



Series: When Worlds Collide (but done RIGHT) [1]
Category: Teenage Mutant Ninja Turtles (TV 2012), Teenage Mutant Ninja Turtles - All Media Types
Genre: Alien Invasion, Canon Compliant, Canon-Typical Violence, Gen, Implied Relationships, Male-Female Friendship, Organized Crime, Tension, Tumblr Prompt, casey has a lot of explaining to do about how he knows a gal like shini, god dammnit, i'm here to answer that question right now, tfw you're the token humans of the group, that's bc the WORLD IS BEING INVADED AGAIN, where the fuck were shini and casey during When World's Collide?
Language: English
Status: Completed
Published: 2017-08-23
Updated: 2017-08-23
Packaged: 2018-12-19 03:04:55
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,706
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11888610
Author URL: https://archiveofourown.org/users/Werepirechick/pseuds/Werepirechick
Summary: Where were Shinigami and Casey during the umpteenth alien invasion of New York?Holding down the fort, naturally.





	Defense

**Author's Note:**

> someone on tumblr wanted me to write a filler fic for canon, since When World's Collide (AKA the worst two-part episode special i've seen since Owari/Requiem or however that line up went) and naturally, i couldn't just leave my gorgeous murder lady and garbage son without a proper treatment!
> 
> honestly, this was such an obvious concept to come up with. i'm actually pissed the well paid, very experienced board of writers for TMNT couldn't think of it themselves.

In the middle of locking down the whole compound, Shinigami’s phone rings.

It could be Karai, _finally_ summoning them all to battle instead of leaving them all here twiddling their thumbs- so she answers it immediately.

It’s not Karai.

 _“Hey, so. The world’s kind of ending for the fifth time or something,”_ Says a teenage boy over the line; the one that clings to the turtles and April like a stubborn bramble, despite obviously lacking any formal training.

“I hadn’t noticed,” Shini replies dryly, burying her thrum of worry underneath her persona. It’s not Karai on the phone, and thus her Senpai remains out of contact and unaccounted for. Worrying. “Why are you calling, I would have thought you’d be throwing yourself into the fray along with the turtles.”

_“In a sitch like this, kind of not my job.”_

“No?”

_“Nope.”_

This doesn’t sound like something Casey Jones would do, from what Shinigami has observed of him. He seemed like he’d be the sort to keep charging into things until he either won or died, whichever came first.

“Why?” Shinigami asks, because even with all the chaos happening around her and her heart clenching with fear about Karai being _missing_ and _in danger,_ her curiosity remains present as always.

 _“The brothers don’t really got people to worry about up here,”_ Casey Jones says tightly. The sound of screeching tires and muffled yelling momentarily takes over the phone line, and then he adds, “ _-but me an’ April_ do.”

“…ah,” Shinigami says, garnering his situation.

 _“I have a van full of relatives and kind of in-laws, and not a whole lot of options for a hideout. Lair’s too far and- FUCK,”_ Tires scream even louder, and Shinigami thinks she hears something go _thoom_ , followed by an explosion. _“Long story short I need a place to crash before we_ literally _crash! You got- you guys have basically a fortress, right? The bugs won’t be able to get inside?”_

The flurry of evacuation, to lower levels, is still happening around Shinigami. Foot soldiers, technicians, and medical staff, all moving into the sublevels of the church compound. As soon as everything vital and every _one_ vital is down there, she’s going down herself, and they’re locking the reinforced doors behind them. No one will get in, _or_ out, until Karai calls to tell them the apocalypse is over.

Or, she doesn’t call at all, and then the decision of their next move will fall to Shinigami.

…they admittedly have room for a few more.

Shinigami has always prided herself on looking out for her few trusted close ones, leaving everyone else to do what they will, and survive if they can.

But, Casey Jones _is_ a member of Karai’s extended half family… _and_ he helped save her Senpai, once or twice before.

Shinigami sighs. Debts are not something she is fond of.

“The bugs won’t be able to get inside, no,” Shinigami says, and then adds without pause, “How soon will you be able to get here? We’re locking down as we speak.”

 _“Kind of already here,_ ” Jones says, because of _course_ he does. _“Open your back door so we don’t all get abducted by FUCKING SPACE BUGS-”_

The line cuts off. Shinigami doesn’t have to wonder why.

She sends a small squadron to retrieve Jones and his people. Let it never be said she didn’t do a kind thing, or leave a debt like this unpaid.

\--/--

Casey Jones is many things, and fears almost nothing.

But, because he’s an older brother, a son- he’s scared shitless of losing the small family he’s got. Hence the calling of one person he never thought he would.

He’ll thank Leo for pushing them to have _all_ numbers of their social group, later. This might’ve saved his family’s life and Mr. O’Neil and Ms. O’Neil’s too. Probably his as well, since he would’ve stood between them and any stupid alien bug who attacked them until he couldn’t anymore, and then would have stood _longer._

As much as he hates being pulled back to defense, Casey supposes he sees the purpose to it. Maybe he can’t blow things up with his mind, or hide a hundred and one ninja weapons on his person- but he _can_ keep a promise, and he can face down a whole army for the sake of that promise.

Especially when it’s his little sister and dad standing behind him, and the last two human relatives April’s got.

It still sucks _royally,_ hiding in an underground laboratory while the world goes to shit. While his friends are off risking their lives for the millionth time, and he’s not there to back them up.

His father isn’t making anything easier, questioning Casey again and again why they’re hiding in what resembles very strongly a _supervillain’s_ _lair_ , and currently surrounded by armed men and women who do nothing to dispel that impression.

“Dad, please, don’t ask about- any of this,” Casey waves his hand at the stone walls and creepy lighting of what used to be Stockman’s lab. Fuck that guy, for real. “If you don’t know nothin’, then you have deniability still.”

His dad’s eyebrows sink a little lower. Ah hell, that would be the ‘ _I’m worried_ and _angry right now’_ expression. _“Deniability?”_ His dad asks in a low voice. “Arnold Casey Jones, just what in _god’s name_ did you get yourself mixed up in?!”

Casey winces at the full naming. Oh boy. “Now see, that’s the part where you don’t ask and keep your deniability…”

“Mr. Jones,” A smooth, sly voice interjects before Casey’s dad can work up another round. Shinigami’s heels click against the stone floor, cool gaze and a coy smile in place as she approaches. Casey sees his dad stand straighter, on guard, and notes that his thirteen year old sister watches the older woman with interest. Well, can’t fault his sister for her taste. Shinigami is about as beautiful as she is deadly. Which is very.

“Your son assisted us… in saving the life of a very dear person to me, not more than a few months ago,” Shinigami says, and Casey knows that’s not entirely a lie. “Myself and that person gave him a single favor to use as he needed, in exchange for that assistance. He was simply in the right place, at the right time, and we’ve hardly interacted since.”

“So… you’re saying my kid saved someone you’re close to, but you didn’t drag him into any of…” Casey’s dad glances around at the Foot soldiers milling around, clearly uncomfortable. His hand on Casey’s little sister, placed around her shoulders and keeping her close, makes that even clearer. “…this?”

“No,” Shinigami says, still smiling. Casey only vaguely knows her through their mutual social group, but it’s still enough that he can spot the subtle, but purposeful beguiling. “Your son has only been someone we met with… very, very rarely. He has never been involved with the clan’s business.”

Kind of a lie? Casey doesn’t mind, though. Anything to keep his dad from prying further, and possibly finding out about the shit ton of _really dangerous_ stuff he’s been involved with. Or finding out his friends, and his situation with them.

Casey’s dad examines Shinigami for a moment longer, and then nods once.  He’s probably decided to not look a gift horse in the mouth, at least until they get home and he’s got Casey cornered for questioning. Won’t that be fun.

“Thank you for saving us,” He says, and Casey knows it’s sincere despite the gruff tone. His eyes go to Casey’s sister, same time as his do. They’re both probably thinking the same thing. “I don’t know what we would have done otherwise.”

Shinigami smiles a little wider; kind, but mysterious. “It’s no trouble, simply repaying a debt. Now, if you would please follow one of my attendants, they’ll take you to a place you can rest until this whole- invasion nonsense is over...”

Shinigami works her magic, (possibly literally?), and has her Foot soldiers lead Casey’s family away. He lingers, because he’s got something to say, and because he really doesn’t want to hold still long enough for his dad to potentially start asking questions again.

“Hey, Shinigami?” He asks, getting the woman to turn her eyes to him. He meets them evenly, because he’s gotten kind of used to being around people with subtly dangerous gazes. “Thank you, really. I… it’s my job to take care of our families when everything goes to shit, and I don’t want to think about how this could’ve gone down without you lettin’ us in. So. Thank you.”

Shinigami looks at him for a long moment, and then smiles one of her more unreadable expressions. “Like I said, Jones, it is simply repaying a debt. For all the times you saved my Senpai.”

\--/--

Hour four drags by, and Shinigami fights with herself about going after her dearest Karai.

The news channels have all gone down, and only shaky videos taken and posted from cameras remain to relay the situation aboveground. From the looks of things, it’s not going well.

Her scythes weigh heavy on her hips, begging for use and urging her to slip away to search for Karai. Damn the Foot clan- the only reason she ever joined was to be by her Senpai’s side. There’s nothing holding her here except for Karai’s wish that should the worst happen… Shinigami is to continue the Foot on its current course, until she finds a suitable heir.

Shinigami doesn’t want to lead the Foot, or find an heir. She wants to be by Karai’s side, protecting her back.

Her fingers trace the very edges of her blades, not drawing them but unable to keep her hands off them completely. There’s no telling what’s going on with her Senpai at the moment. She could be in danger, she could be injured, she could be…

The phones won’t connect anymore, not because they’re underground, but because Karai’s phone seems to have turned itself off. And the turtles’ and April’s…

All of those phones, turned off at such a dire time? All at once? It’s suspicious, and worrying.

Shinigami is barely holding herself within the safe zone of the church. It’s all she can do to not let panic and passion seize her, and send her running through the chaos stricken streets to find Karai.

“Got the battle-itches?”

Shinigami is caught pf guard by the absurdity of that sentence, enough that she actually stutters internally. She turns, to find Jones leaning on a hockey stick, looking as drawn and frustrated as Shinigami feels.

“Excuse me?” Shinigami asks. In all her years, _that’s_ a new one for a man to try with her.

“You wanna be up there too, am I right?” He clarifies, nodding vaguely upwards. “I get that feel. This is drivin’ me nuts.”

Shinigami considers him for a moment; the extended hand of understanding and sympathy.

She takes it.

“I… worry for Karai’s safety,” Shinigami admits under her breath, wary of passing soldiers hearing her concern. Their leader must be unbeatable, unbreakable; she can’t be seen as anything else, no matter how much Shinigami fears for her dear Karai.

Jones rubs his face, sighing harshly. “Yeah, I figured you’d be. I’m worrin’ about the brothers and April, personally speaking. But they got each other, all seven of ‘em and whoever else they dragged into things. They’ll… they’ll be fine.”

“You say that, but you don’t look like you believe it,” Shinigami points out softly.

Jones smiles crookedly, more of a grimace, and then laughs. “What? Nah. Not me. They always come through, no matter what. It’s just the _waiting_ that gets to me, you know? I’m not made to just sit around when there’s ass to kick. They need Casey Jones out there with ‘em, backing them all up and taking point. Or something like that.”

Shinigami thinks for a moment, and then says, “I should be up there with Karai, protecting her back and taking her right flank. Not sitting here and waiting around like some abandoned sentinel.” She smiles wryly. “Or something like that.”

Jones laughs, a sort of startled sound. He seems to relax a little, out of the wary stance and gait he’s been carrying since the moment he set foot inside Shinigami’s realm of rule. It’s understandable, since their friends and loved ones are likely in mortal peril, and this is far from part of his territory.

A moment of silence passes, the two of them standing in the entrance to Stockman’s old laboratory. It’s not as awkward or strange like Shinigami might’ve guessed it would be. There’s something to mutual understanding, after all.

A low volume siren suddenly goes off, and Shinigami’s men and women start rushing around. Within seconds, a Foot soldier approaches Shinigami, and relays that bugs have breached the upper levels. From what their small team of scientists can discern, the aliens are able to tell there are a large number of humans below ground, and are looking to break through the doors.

Shinigami glances at Jones.

He’s already grinning, more so baring his teeth in challenge.

Shinigami snaps her fingers, and gives the order to engage with utmost caution. And to get the hell out of their way.

They’ve waited around long enough. Now, they fight.

\--/--

When all is said and done, and bug aliens start falling dead without Casey hardly tapping them, he figures things could’ve been a lot worse than they turned out.

Sure, New York is pretty much coated in a layer of slime and guts, but they won and everyone is mostly safe. He knows not everyone was as lucky as his dad and sister, or April’s father and aunt, but hey. He got his own people to safety, and then he _kept_ them safe.

It’s enough for him. Infinitely better than the alternative.

He will never, _ever_ leave them behind again. Not even if the world starts falling apart under his feet a second time, he _won’t._

He refuses to go through that again.

Shinigami somehow has barely a hair out of place, despite being right on the frontlines with him as they drove out the bugs from the church. Casey sees the angle of liking a lady like this, the sort that’s untouchable by anything around her. But, personally speaking, he still digs the blood streaked, messy haired, dirt smeared red-head type more.

He’s a little biased, but everyone knows that.

As he ushers his dad, sis, and the O’Neil’s into the Party Wagon, he’s a little surprised to see Shinigami seeing them off. He waits until she approaches, and then waits further to hear what she’s got to say.

“If you see Senpai before me…” Shinigami’s mask of aloofness breaks for a moment, exposing genuine emotions. “Please remind her to call. And tell her the Foot remains as she left it, and that…” She mends the cracks, and then they’re gone. “And that’s it. I apologize, I am a little tired.”

Casey jerks a nod. He gets it without having to ask at all. Being separated from the people really important to you sucks, and it’s not an easy thing to admit aloud.

He sticks out a hand. “I’ll make sure she calls you, if she hasn’t already by the time I meet up with everyone else. I’ll find ‘em soon as I drop my folks and April’s off, okay?”

Shinigami blinks at his hand, and then slowly takes it. She shakes once, and then they let go.

“I wish you and yours good luck, and I hope no serious harm has come to your dear ones,” Shinigami says, and for once, Casey’s pretty sure every word is real.

“Yeah, same to you. See you around.”

Shinigami is back to being unreadable and masked by the time he starts to leave, and gives only an enigmatic smile.

He gets in the Party Wagon, and starts weaving through the disaster zone New York has become once again. His father and sister sit tensely beside him, watching the damage go by with cautious eyes. April’s aunt sits in the back, trying to help Kirby keep calm as they navigate the fresh trauma in their lives. Casey feels kind of badly for all of them; they’re not as adjusted or familiar with insanity as he is, or as ready to embrace it.

He gets them home safely though, and promises to come right back as soon as he has April and his friends again. His father gives him a deeply concerned look, but lets him go. Kirby who _knows_ how his daughter and their friends are mixed up in this, just gives him a pale, but thankful smile.

His little sister grabs him before he runs out the door, and drags him into as bone crushing a hug as her thin arms can manage.

“Don’t be an idiot,” She whispers in his ear. “and come home soon, okay?”

He squeezes her back, tight. He could’ve lost her a lot of times over the years, and he hasn’t refused a hug since the first time. “I’ll be back before you even miss me.”

Walking away from his family is hard, because the sense of danger isn’t quite gone yet, but he manages it because he still has people to find.

His phone finally lights up, as he’s circling the worst impact zones, and he answers it immediately.

“You son of a fuck,” He says into the phone. “ _None_ of you could’ve kept your fuckin’ phones on?”

 _“Sorry, electrical interference scrambled the signals,”_ Donnie says, sounding tired and achingly relieved. _“Newtralizer came back, able to_ teleport _of all things, and yeah, that screwed up every single cell tower in the area.”_

“How so?”

 _“Fuck if I know. I’m tired and I’m just trying to get over the fact that yet_ another _of my brothers has died and come back to life within minutes of each event.”_

“Oof,” Casey winces with a grimace. “Which one?”

 _“Mikey,”_ Donnie replies flatly. Casey winces again, because _yikes_.

“He okay?”

 _“He’s-”_ Donnie sighs. _“He’s_ naked _, and breathing, and apparently okay despite blowing himself up? God I don’t know. I have to do a proper examination later. Anyways. We’re on a rooftop in the middle of day, and the air force is doing circles nearby. Please come get us before we have to break out of a lab_ again _.”_ A pause, and then he adds. _“I’m really glad you’re okay, by the way. Did you get to somewhere safe with yours and April’s families?”_

“Shinigami let us into the church, it was real nice of her,” Casey says. “And I’m glad you’re okay, too. I’m glad all of you guys are okay. How’s April?”

_“I think she has the third highest kill count for bugs today, but only on the account of Y'Gythgba decapitating anything that got within ten feet of her, and Mikey and his suicide bomb act. I’d say she’ll be fine after a good shower and food. Same with all of us, honestly.”_

“I could eat,” Casey turns the steering wheel, avoiding a sizable pothole. “Hey, location?”

Donnie rattles off the address, and Casey breaks a few driving laws to make it there in less than ten minutes. They shoot shit on and off as Casey drivers over cracked roads and obliterated sidewalks.

 _“I think I’m going to have to hold him down until the shock wears off- he won’t stop_ bouncing around _, Casey.”_

“Yeah, Mike’s a little shaky on the whole self-preservation thing.”

_“None of my brothers understand basic first-aid protocols. And like you have any leg to stand on, adrenaline junkie.”_

“You’re just a worry-wart, nothin’ can kill Casey Jones.”

_“Sure. I’ll make certain that’s carved on your tombstone.”_

Casey laughs, feeling light, and he draws a chuckle out of Donnie as he does.

Seeing Donnie, April, and all the rest (plus Y’Gythgba, because she’s sticking around apparently) clamber off the roof is a comforting sight. No one is limping more than worth worrying, no one has cuts beyond a band-aid level, and they’re all accounted for.

Raph is grinning, with a black eye and an arm around Mikey’s shoulders, who is beaming at everyone around him and very naked. Leo is walking with Karai, and Y’Gygthba, and none of those three look any worse for wear beyond alien guck caked to them. Donnie has what looks like alien blood splattered all over him, same as April, and everyone else. April’s eyes are bright though, alert and high on victory as she smiles at Casey, and though Donnie looks tired as he usually does, he gives a weary smile as they all approach.

It’s the best damn sight Casey’s seen all day.

Casey grins, and salutes lazily as his second family and co. gets into the van. Safe and sound, and where he can watch their backs again.

\--/--

When Karai slips in through the window of the church, Shinigami feels her whole body relax.

Her Senpai smiles, wide and confident despite the filth and small injuries all over her. Shinigami can’t help but smile back, warm to her toes with relief.

The throne room is crossed in a blink of an eye, and then Karai is warm and safe in Shinigami’s arms.

Curling around Karai, in a brief moment of care before anyone sees, solves everything that had been snarling itself with worry in her chest.

“Welcome back,” Shinigami says softly, holding Karai close as she can without hurting her.

Karai’s arms tighten around her neck, and she replies, “Glad to be back.”

When they break apart, Shinigami allows herself one last indulgence to brush Karai’s messy bangs from her face. Her Senpai’s makeup is slightly smudged on the edges, and a blooming bruise graces her jaw. Well, that won’t do at all.

“Come,” Shinigami says, taking Karai’s hand and pulling her towards the exit. “I have the medical staff, a bath, and dinner ready. You look like you need all three.”

“That sounds wonderful,” Karai says, gratitude clear in her tone. As they walk briskly, her hand around Shinigami’s is tight, unrelenting, and so very alive.

It’s more of a relief than anything could be.

**Author's Note:**

> you know me, couldn't resist heavily implying my otp's. if canon won't even give resolution to the tension, then i'll just run with it to spite the writers.
> 
> also: who agrees with me that this was a really obvious thing to think of? seriously, it would have explained everything about where casey and shini had been, and it would have been /believable/. just an offhand mention, a cameo phone call, that's all it would have taken!
> 
> just another reason why WWC was a hot disaster. :/
> 
> oh well. i fixed it, kind of. and i'll be posting a sequel fic to this really quick, about mikey and the bros and how mikey freaking DIED, or at least they thought he had, and that wasn't addressed at ALL??? fuck canon and its inability to give believable emotional reactions to anyone.
> 
> leave a comment please and thank you, and [please consider buying me a Ko-fi ](https://ko-fi.com/A3022DE7). rewards through the link for those who do. :D


End file.
